Tourette Syndrome (TS) is a common genetic pediatric neuropsychiatric disorder. Manifest as chronic motor and vocal tics, it affects approximately 0.3-1% of children, with significant negative impact on quality of life. TS is associated with deficits in impulse regulation and executive control functions. The brain's executive control systems are thought to be anatomically separate from downstream moment-to-moment processing systems and to consist of networks of functionally diverse regions. The interactions of these control systems with processing systems have been implicated in TS. A key idea underlying this exploratory proposal is that TS arises from the atypical development of networks of control regions and their interactions, as opposed to the atypical functioning of any particular brain region. Medications that relieve tics in TS may also result in an improvement in control abilities, and a normalization of both evoked activity within control regions and of functional connectivity between regions comprising control networks. We hypothesis that the anomalous patterns of brain activation and functional connectivity observed in TS will be ameliorated by medications that treat TS. Understanding the brain's control networks are affected by medications may lay the foundation for earlier diagnosis and more effective therapies for TS and other pediatric neuropsychiatric disorders. PUBLIC HEALTH RELEVANCE: This proposal aims to use longitudinal task-based fMRI and functional connectivity MRI to characterize the development of control networks in pediatric Tourette Syndrome and how those networks respond to pharmacotherapeutic intervention. Understanding how networks of brain regions involved in control are affected by pharmacotherapy in patient with Tourette Syndrome may lay the foundation for earlier diagnosis, more accurate prognosis, and more effective therapies